Patents by Inventor Takafumi Sano

Takafumi Sano 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).

  • Patent number: 9539804
    Abstract: There is provided a liquid discharging apparatus including: a modulation portion which generates a modulation signal pulse-modulated from a source signal; a gate driver which generates an amplification control signal based on the modulation signal; a boosting circuit which boosts and supplies a voltage to the gate driver; a transistor which generates an amplification modulation signal amplified from the modulation signal based on the amplification control signal; a low pass filter which demodulates the amplification modulation signal and generates a driving signal; and a piezoelectric element which is displaced as the driving signal is applied, in which the gate driver and the boosting circuit are electrically connected to a common ground terminal, and in which a wiring impedance between the ground terminal and the gate driver is smaller than a wiring impedance between the ground terminal and the boosting circuit.
    Type: Grant
    Filed: November 24, 2015
    Date of Patent: January 10, 2017
    Assignee: Seiko Epson Corporation
    Inventor: Takafumi Sano
  • Patent number: 9533493
    Abstract: There is provided a liquid discharging apparatus including: a modulation portion which generates a modulation signal pulse-modulated from a source signal; a gate driver which generates an amplification control signal based on the modulation signal; a transistor which generates an amplification modulation signal amplified from the modulation signal based on the amplification control signal; a low pass filter which demodulates the amplification modulation signal and generates a driving signal; a piezoelectric element which is displaced as the driving signal is applied; a first power source portion which applies a constant voltage signal to a terminal which is different from a terminal to which the driving signal of the piezoelectric element is applied; and a temperature detection portion which detects temperature, in which the first power source portion is disposed on the shortest straight path between the temperature detection portion and the gate driver.
    Type: Grant
    Filed: November 19, 2015
    Date of Patent: January 3, 2017
    Assignee: Seiko Epson Corporation
    Inventor: Takafumi Sano
  • Patent number: 9475283
    Abstract: A liquid discharging apparatus includes a modulation portion that generates a modulation signal obtained by pulse-modulating a source signal; an amplifier that includes a first gate driver generating a first amplification control signal based on the modulation signal, a second gate driver generating a second amplification control signal based on the modulation signal, a first transistor operating based on the first amplification control signal, a second transistor connected to the first transistor on a low-potential side in series and operating based on the second amplification control signal; an operation control portion that controls operations of the first gate driver and the second gate driver; a low-pass filter that generates a driving signal by demodulating an amplification modulation signal generated based on operations of the first transistor and the second transistor; and a piezoelectric element that is displaced by applying the driving signal.
    Type: Grant
    Filed: January 20, 2016
    Date of Patent: October 25, 2016
    Assignee: Seiko Epson Corporation
    Inventor: Takafumi Sano
  • Patent number: 9475284
    Abstract: A liquid discharging apparatus includes a modulation portion that generates a modulation signal obtained by pulse-modulating a source signal; an amplifier that includes a first transistor and a second transistor operating based on the modulation signal; an operation control portion that controls operations of the amplifier; a low-pass filter that generates a driving signal by demodulating an amplification modulation signal generated based on operations of the first transistor and the second transistor; and a piezoelectric element that is displaced by applying the driving signal. The operation control portion performs a stopping process that stops an operation of the amplifier by allowing the first transistor to be in a non-conductive state in which a current does not flow through the first transistor and the second transistor to be in a conductive state in which the current flows through the second transistor.
    Type: Grant
    Filed: January 21, 2016
    Date of Patent: October 25, 2016
    Assignee: Seiko Epson Corporation
    Inventor: Takafumi Sano
  • Publication number: 20160236464
    Abstract: A liquid discharging apparatus includes a modulation portion that generates a modulation signal obtained by pulse-modulating a source signal; an amplifier that includes a first gate driver generating a first amplification control signal based on the modulation signal, a second gate driver generating a second amplification control signal based on the modulation signal, a first transistor operating based on the first amplification control signal, a second transistor connected to the first transistor on a low-potential side in series and operating based on the second amplification control signal; an operation control portion that controls operations of the first gate driver and the second gate driver; a low-pass filter that generates a driving signal by demodulating an amplification modulation signal generated based on operations of the first transistor and the second transistor; and a piezoelectric element that is displaced by applying the driving signal.
    Type: Application
    Filed: January 20, 2016
    Publication date: August 18, 2016
    Inventor: Takafumi SANO
  • Publication number: 20160221332
    Abstract: A liquid discharging apparatus includes a modulation portion that generates a modulation signal obtained by pulse-modulating a source signal; an amplifier that includes a first transistor and a second transistor operating based on the modulation signal; an operation control portion that controls operations of the amplifier; a low-pass filter that generates a driving signal by demodulating an amplification modulation signal generated based on operations of the first transistor and the second transistor; and a piezoelectric element that is displaced by applying the driving signal. The operation control portion performs a stopping process that stops an operation of the amplifier by allowing the first transistor to be in a non-conductive state in which a current does not flow through the first transistor and the second transistor to be in a conductive state in which the current flows through the second transistor.
    Type: Application
    Filed: January 21, 2016
    Publication date: August 4, 2016
    Inventor: Takafumi SANO
  • Publication number: 20160221333
    Abstract: A liquid discharging apparatus includes a modulation portion that generates a modulation signal obtained by pulse-modulating a source signal; an amplifier that includes a gate driver generating an amplification control signal based on the modulation signal, a bootstrap circuit supplying power to the gate driver, a power source circuit supplying power to the gate driver and the bootstrap circuit, and a transistor generating the amplification modulation signal that is obtained by amplifying the modulation signal based on amplification control signal; a low-pass filter that generates the driving signal by demodulating the amplification modulation signal; a piezoelectric element that is displaced by applying the driving signal; and a control portion that controls an operation of the amplifier. The control portion performs a second process of starting an amplification operation of the amplifier after a first process of performing supply of power to the bootstrap circuit.
    Type: Application
    Filed: January 21, 2016
    Publication date: August 4, 2016
    Inventor: Takafumi SANO
  • Publication number: 20160221331
    Abstract: A liquid discharging apparatus includes a modulation portion that generates a modulation signal obtained by pulse-modulating a source signal; a switching element that generates an amplification modulation signal obtained by amplifying the modulation signal; a low-pass filter that generates a driving signal by demodulating the amplification modulation signal; a piezoelectric element that is displaced by applying the driving signal; a selection portion that is configured to include a transistor and selects whether or not the driving signal is applied to the piezoelectric element; and a detection portion that detects lowering of a power source voltage supplied to the selection portion. The detection portion performs control for lowering a voltage of the driving signal if lowering of the power source voltage is detected.
    Type: Application
    Filed: January 19, 2016
    Publication date: August 4, 2016
    Inventor: Takafumi SANO
  • Publication number: 20160167371
    Abstract: There is provided a liquid discharging apparatus including: a modulation portion which generates a modulation signal pulse-modulated from a source signal; a gate driver which generates an amplification control signal based on the modulation signal; a boosting circuit which boosts and supplies a voltage to the gate driver; a transistor which generates an amplification modulation signal amplified from the modulation signal based on the amplification control signal; a low pass filter which demodulates the amplification modulation signal and generates a driving signal; and a piezoelectric element which is displaced as the driving signal is applied, in which the gate driver and the boosting circuit are electrically connected to a common ground terminal, and in which a wiring impedance between the ground terminal and the gate driver is smaller than a wiring impedance between the ground terminal and the boosting circuit.
    Type: Application
    Filed: November 24, 2015
    Publication date: June 16, 2016
    Inventor: Takafumi SANO
  • Publication number: 20160167368
    Abstract: There is provided a liquid discharging apparatus including: a modulation portion which generates a modulation signal pulse-modulated from a source signal; a gate driver which generates an amplification control signal based on the modulation signal; a transistor which generates an amplification modulation signal amplified from the modulation signal based on the amplification control signal; a low pass filter which demodulates the amplification modulation signal and generates a driving signal; a piezoelectric element which is displaced as the driving signal is applied; a first power source portion which applies a constant voltage signal to a terminal which is different from a terminal to which the driving signal of the piezoelectric element is applied; and a temperature detection portion which detects temperature, in which the first power source portion is disposed on the shortest straight path between the temperature detection portion and the gate driver.
    Type: Application
    Filed: November 19, 2015
    Publication date: June 16, 2016
    Inventor: Takafumi SANO
  • Publication number: 20160159088
    Abstract: There is provided a liquid discharging apparatus including: an original driving signal generation portion which generates an original driving signal based on a source signal; a driving signal generation portion which generates a driving signal based on the original driving signal; a reference voltage generation portion which generates a first reference voltage and a second reference voltage adjusted based on an adjustment signal, and supplies the voltage to the original driving signal generation portion; a piezoelectric element which is displaced as the driving signal is applied; a cavity; and a nozzle, and discharges the liquid inside the cavity as liquid droplets in accordance with the change in the internal volume of the cavity, in which adjustment resolution of the first reference voltage is lower than adjustment resolution of the second reference voltage.
    Type: Application
    Filed: November 2, 2015
    Publication date: June 9, 2016
    Inventor: Takafumi SANO
  • Patent number: 9262972
    Abstract: A method for controlling an electro-optic device switches between a first driving scheme for changing an optical state between a-number of optical states and a second driving scheme for changing an optical state between b-number of optical states (b>a). In the first driving scheme, an integrated value W (A?B) of drive voltage and drive time when changing an optical state A to an optical state B, and an integrated value W (B?A) of drive voltage and drive time when changing the pixel from the optical state B to the optical state A satisfy a relation of W (A?B)=?W (B?A), and the integrated value W (A?B) and W (B?A) for the optical state A and B in the second driving scheme are equal to the integrated value W (A?B) and W (B?A) in the first driving scheme, respectively.
    Type: Grant
    Filed: July 23, 2013
    Date of Patent: February 16, 2016
    Assignee: SEIKO EPSON CORPORATION
    Inventors: Keitaro Fujimori, Takafumi Sano
  • Patent number: 9196201
    Abstract: A method for controlling an electro-optic device includes a third, a fourth, a first, and a second control steps of supplying a third, a fourth, a first, and a second voltage pulse, in this order. In the first control step, a first limit optical state is reached. In the second control step, a first intermediate optical state is reached. The period of each of the third control step and the fourth control step is set to satisfy a relation W (A?B)=?W (B?A), where W (A?B) is an integrated value of drive voltage and drive time when changing the pixel from an optical state A to an optical state B, and W (B?A) is an integrated value of drive voltage and drive time when changing the pixel from the optical state B to the optical state A.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: November 24, 2015
    Assignee: SEIKO EPSON CORPORATION
    Inventors: Keitaro Fujimori, Takafumi Sano
  • Publication number: 20150314595
    Abstract: A liquid ejecting apparatus includes a modulation circuit that performs pulse modulation on an original signal to generate a modulated signal; a pair of transistors that generate an amplified modulated signal amplified from the modulated signal; a lowpass filter that smoothes the amplified modulated signal to generate a driving signal; an AD converter that performs AD conversion on a voltage based on the driving signal; a piezoelectric element that is displaced to eject a liquid when the driving signal is applied. The AD converter includes at least K (where K is an integer equal to or greater than 2) capacitors and a controller that causes the K capacitors to sample voltages based on the driving signal at temporally different timings, and subsequently equalizes the voltages and outputs a result of the AD conversion based on the equalized voltage.
    Type: Application
    Filed: April 30, 2015
    Publication date: November 5, 2015
    Inventor: Takafumi SANO
  • Publication number: 20140028660
    Abstract: A method for controlling an electro-optic device switches between a first driving scheme for changing an optical state between a-number of optical states and a second driving scheme for changing an optical state between b-number of optical states (b>a). In the first driving scheme, an integrated value W (A?B) of drive voltage and drive time when changing an optical state A to an optical state B, and an integrated value W (B?A) of drive voltage and drive time when changing the pixel from the optical state B to the optical state A satisfy a relation of W (A?B)=?W (B?A), and the integrated value W (A?B) and W (B?A) for the optical state A and B in the second driving scheme are equal to the integrated value W (A?B) and W (B?A) in the first driving scheme, respectively.
    Type: Application
    Filed: July 23, 2013
    Publication date: January 30, 2014
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Keitaro FUJIMORI, Takafumi SANO
  • Publication number: 20130249886
    Abstract: A method for controlling an electro-optic device includes a third, a fourth, a first, and a second control steps of supplying a third, a fourth, a first, and a second voltage pulse, in this order. In the first control step, a first limit optical state is reached. In the second control step, a first intermediate optical state is reached. The period of each of the third control step and the fourth control step is set to satisfy a relation W (A?B)=?W (B?A), where W (A?B) is an integrated value of drive voltage and drive time when changing the pixel from an optical state A to an optical state B, and W (B?A) is an integrated value of drive voltage and drive time when changing the pixel from the optical state B to the optical state A.
    Type: Application
    Filed: March 14, 2013
    Publication date: September 26, 2013
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Keitaro FUJIMORI, Takafumi SANO
  • Patent number: 8420994
    Abstract: A solid-state imaging device includes a light receiving section having a plurality of threshold voltage modulation pixel circuits each configured including a MOS transistor having a gate electrode connected to a supply terminal of a gate voltage of a vertical scanning circuit, and a source electrode connected to one end of each capacitor of a line memory group via a switching element, and a photodiode having an anode connected to a back-gate electrode of the MOS transistor and a cathode connected to a drain electrode thereof, and a buffer circuit having an input terminal connected to a supply line of a control voltage of the control voltage supply means adapted to supply the vertical scanning circuit with the control voltage, and an output terminal connected to the other end of each capacitor, and having a signal transfer characteristic the same as that of the pixel circuit.
    Type: Grant
    Filed: March 18, 2010
    Date of Patent: April 16, 2013
    Assignee: Seiko Epson Corporation
    Inventors: Takafumi Sano, Naohiko Aoyagi
  • Publication number: 20100308208
    Abstract: A solid-state imaging device includes a light receiving section having a plurality of threshold voltage modulation pixel circuits each configured including a MOS transistor having a gate electrode connected to a supply terminal of a gate voltage of a vertical scanning circuit, and a source electrode connected to one end of each capacitor of a line memory group via a switching element, and a photodiode having an anode connected to a back-gate electrode of the MOS transistor and a cathode connected to a drain electrode thereof, and a buffer circuit having an input terminal connected to a supply line of a control voltage of the control voltage supply means adapted to supply the vertical scanning circuit with the control voltage, and an output terminal connected to the other end of each capacitor, and having a signal transfer characteristic the same as that of the pixel circuit.
    Type: Application
    Filed: March 18, 2010
    Publication date: December 9, 2010
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Takafumi SANO, Naohiko AOYAGI
  • Patent number: 7692702
    Abstract: A solid-state imaging device includes a substrate, a sensor cell array disposed on the substrate, the sensor cell array having a plurality of sensor cells arranged in a matrix, a plurality of signal lines for transferring an image signal output from each of the sensor cells, a plurality of amplifiers connected to at least one of the signal lines, each of the amplifiers including a first capacitance having a first end connected to one of the signal lines, an inversion amplifier having an input end connected to a second end of the first capacitance, a second capacitance connected between the input end and an output end of the inversion amplifier, a switch connected between the input and output ends of the inversion amplifier to reset the second capacitance and a third capacitance having a first end connected to a control line and a second end connected to the input end of the inversion amplifier, and a control voltage supply circuit for supplying one of first and second voltages to the control line.
    Type: Grant
    Filed: June 22, 2006
    Date of Patent: April 6, 2010
    Assignee: Seiko Epson Corporation
    Inventor: Takafumi Sano
  • Patent number: 7656338
    Abstract: An analog-digital converter performs AD conversion of an upper m bits by sequential comparison, and performs AD conversion of a lower n bits by integration. This increases accuracy, reduces power consumption during operation, reduces variation between analog signals and digital signals, and reduces the required layout area by decreasing the number of capacitor elements needed. Also, the AD conversion of the n bits by integration is performed by ramp voltage quantized with a margin of k bits of the lower n bits. As such, preferable AD conversion characteristics can be obtained when offset or the like is produced in a DA conversion circuit for generating ramp voltage.
    Type: Grant
    Filed: May 22, 2008
    Date of Patent: February 2, 2010
    Assignee: Seiko Epson Corporation
    Inventor: Takafumi Sano