Patents by Inventor Akira Yumoto

Akira Yumoto 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: 20060119552
    Abstract: An active-matrix display device employs current-programmed-type pixel circuits and performs the writing data to each of pixels on a line-by-line basis. The active-matrix display device having a matrix of current-programmed-type pixel circuits includes a data line driving circuit 15 formed of m current driving circuits (CD) 15-1 to 15-m arranged corresponding to respective data lines 13-1 to 13-m. The data line driving circuit (CD) 15-1 to 15-m holds image data (luminance data herein) in the form of voltage, and then converts the voltage of the image data into a current signal. The current signal is then fed to the data lines 13-1 to 13-m at a time. The image information is thus written on the pixel circuits 11.
    Type: Application
    Filed: January 24, 2006
    Publication date: June 8, 2006
    Inventor: Akira Yumoto
  • Patent number: 7057588
    Abstract: In an active-matrix display device and a method for driving the active-matrix display device, a fifth transistor is connected between a power line and a drain terminal of a first transistor so that a power-supply voltage, namely the fixed voltage required for the compensation of the threshold voltage, is supplied by the power line via a fifth transistor and not by a signal line. Thus, a sufficient length of time for the threshold voltage compensation period can be maintained, and a second transistor of each pixel can accurately be compensated for threshold voltage irregularities.
    Type: Grant
    Filed: September 23, 2003
    Date of Patent: June 6, 2006
    Assignee: Sony Corporation
    Inventors: Mitsuru Asano, Akira Yumoto
  • Patent number: 7019717
    Abstract: When a current-writing type pixel circuit is made, it involves a greater number of transistors and TFTs occupy much of the area of the pixel circuit. To alleviate this problem, two pixel circuits (P1, P2) have a first scanning TFT (14), a current-voltage conversion TFT (16), respective second scanning TFTs (15-1, 15-2), capacitors (13-1,13-2), and drive TFTs (12-1, 12-2) for OLED including organic EL elements (11-2, 11-2) of two pixels, for example, in a row direction. In each of the pixel circuits, the first scanning TFT (14) handling a large amount of current (Iw) as compare with current flowing through the OLED (11-2, 11-2), and the current-voltage conversion TFT (16) are shared between two pixels.
    Type: Grant
    Filed: January 11, 2002
    Date of Patent: March 28, 2006
    Assignee: Sony Corporation
    Inventors: Akira Yumoto, Mitsuru Asano
  • Patent number: 7015882
    Abstract: An active-matrix display device employs current-programmed-type pixel circuits and performs the writing data to each of pixels on a line-by-line basis. The active-matrix display device having a matrix of current-programmed-type pixel circuits includes a data line driving circuit 15 formed of m current driving circuits (CD) 15-1 to 15-m arranged corresponding to respective data lines 13-1 to 13-m. The data line driving circuit (CD) 15-1 to 15-m holds image data (luminance data herein) in the form of voltage, and then converts the voltage of the image data into a current signal. The current signal is then fed to the data lines 13-1 to 13-m at a time. The image information is thus written on the pixel circuits 11.
    Type: Grant
    Filed: November 7, 2001
    Date of Patent: March 21, 2006
    Assignee: Sony Corporation
    Inventor: Akira Yumoto
  • Publication number: 20060033429
    Abstract: In a display device including, a display area having a plurality of organic EL devices on a substrate; a peripheral area having a driving circuit for the organic EL devices and surrounding the display area on the substrate; and an organic insulating film covering at least the driving circuit, the organic insulating film has a separating groove which divides itself into the inner part and outer part at the periphery of the display area.
    Type: Application
    Filed: July 29, 2005
    Publication date: February 16, 2006
    Inventors: Hiroshi Fujimura, Masumitsu Ino, Mitsuru Asano, Akira Yumoto, Yuichi Iwase
  • Publication number: 20050200300
    Abstract: A display device including a current drive circuit capable of stably and correctly supplying an intended current to a light emitting element of each pixel without being affected by variations in characteristics of an active element inside the pixel and as a result capable of displaying a high quality image, wherein each pixel comprises a receiving use transistor TFT3 for fetching a signal current Iw from a data line DATA when a scanning line SCAN-A is selected, a conversion use transistor TFT1 for once converting a current level of a fetched signal current Iw to a voltage level and holding the same, and a drive use transistor TFT2 for passing a drive current having a current level in accordance with the held voltage level through a light emitting element OLED. The conversion use thin film transistor TFT1 generates a converted voltage level at its own gate by passing the signal current Iw fetched by the TFT3 through its own channel. A capacitor C holds the voltage level created at the gate of the TFT1.
    Type: Application
    Filed: April 14, 2005
    Publication date: September 15, 2005
    Inventor: Akira Yumoto
  • Publication number: 20050190177
    Abstract: A display device including a current drive circuit capable of stably and correctly supplying an intended current to a light emitting element of each pixel without being affected by variations in characteristics of an active element inside the pixel and as a result capable of displaying a high quality image, wherein each pixel comprises a receiving use transistor TFT3 for fetching a signal current Iw from a data line DATA when a scanning line SCAN-A is selected, a conversion use transistor TFT1 for once converting a current level of a fetched signal current Iw to a voltage level and holding the same, and a drive use transistor TFT2 for passing a drive current having a current level in accordance with the held voltage level through a light emitting element OLED. The conversion use thin film transistor TFT1 generates a converted voltage level at its own gate by passing the signal current Iw fetched by the TFT3 through its own channel. A capacitor C holds the voltage level created at the gate of the TFT1.
    Type: Application
    Filed: April 14, 2005
    Publication date: September 1, 2005
    Inventor: Akira Yumoto
  • Patent number: 6859193
    Abstract: A display including a current drive circuit capable of supplying a desired current to a light-emitting element in each pixel stably and accurately irrespective of the characteristic variations of active elements in the pixel, thereby providing a high-definition image. Each pixel is composed of a receiving transistor (TFT3) for receiving a signal current (1w) from a data ine (data) when a scanning line (scanA) is selected, a converting transistor (TFT1) for converting the current level of the received signal current (1w) to a voltage level and holding the voltage level, and a driving transistor (TFT3) for allowing a drive current having a current level corresponding to the held voltage level to flow through light-emitting element (OLED). The converting thin film transistor (TFT1) generates the converted voltage level at its gate by allowing the signal current (Iw) through its channel, and a capacitor (C) holds the voltage level at the gate of the transistor (TFT1).
    Type: Grant
    Filed: July 14, 2000
    Date of Patent: February 22, 2005
    Assignee: Sony Corporation
    Inventor: Akira Yumoto
  • Publication number: 20040207615
    Abstract: A display device including a current drive circuit capable of stably and correctly supplying an intended current to a light emitting element of each pixel without being affected by variations in characteristics of an active element inside the pixel and as a result capable of displaying a high quality image, wherein each pixel comprises a receiving use transistor TFT3 for fetching a signal current Iw from a data line DATA when a scanning line SCAN-A is selected, a conversion use transistor TFT1 for once converting a current level of a fetched signal current Iw to a voltage level and holding the same, and a drive use transistor TFT2 for passing a drive current having a current level in accordance with the held voltage level through a light emitting element OLED. The conversion use thin film transistor TFT1 generates a converted voltage level at its own gate by passing the signal current Iw fetched by the TFT3 through its own channel. A capacitor C holds the voltage level created at the gate of the TFT1.
    Type: Application
    Filed: February 24, 2004
    Publication date: October 21, 2004
    Inventor: Akira Yumoto
  • Publication number: 20040070557
    Abstract: In an active-matrix display device and a method for driving the active-matrix display device, a fifth transistor is connected between a power line and a drain terminal of a first transistor so that a power-supply voltage, namely the fixed voltage required for the compensation of the threshold voltage, is supplied by the power line via a fifth transistor and not by a signal line. Thus, a sufficient length of time for the threshold voltage compensation period can be maintained, and a second transistor of each pixel can accurately be compensated for threshold voltage irregularities.
    Type: Application
    Filed: September 23, 2003
    Publication date: April 15, 2004
    Inventors: Mitsuru Asano, Akira Yumoto
  • Patent number: 6686699
    Abstract: In an active matrix type organic EL display apparatus, a current bias circuit for feeding a data line with a current in a direction of canceling a writing current is provided for each data line. The current bias circuit includes: a converting unit supplied with information of a value of the driving current to be fed in a form of a current, for converting the supplied current into a form of a voltage; a retaining unit for retaining the voltage obtained by the conversion by the converting unit; and a driving unit for converting the voltage retained by the retaining unit into a current, and feeding the data line with the current as the driving current. The current bias circuit feeds, as a bias current, the driving current in the direction of canceling the brightness data current through each data line, and the value of the bias current is prevented from varying among the data lines.
    Type: Grant
    Filed: May 29, 2002
    Date of Patent: February 3, 2004
    Assignee: Sony Corporation
    Inventor: Akira Yumoto
  • Publication number: 20030128200
    Abstract: An active-matrix display device employs current-programmed-type pixel circuits and performs the writing data to each of pixels on a line-by-line basis. The active-matrix display device having a matrix of current-programmed-type pixel circuits includes a data line driving circuit 15 formed of m current driving circuits (CD) 15-1 to 15-m arranged corresponding to respective data lines 13-1 to 13-m. The data line driving circuit (CD) 15-1 to 15-m holds image data (luminance data herein) in the form of voltage, and then converts the voltage of the image data into a current signal. The current signal is then fed to the data lines 13-1 to 13-m at a time. The image information is thus written on the pixel circuits 11.
    Type: Application
    Filed: November 5, 2002
    Publication date: July 10, 2003
    Inventor: Akira Yumoto
  • Patent number: 6583775
    Abstract: The invention provides an image display apparatus which increases the degree of freedom in designing of an active element of a pixel to allow good designing and can adjust the display brightness freely and simply. Each pixel includes a light emitting element (OLED) with a brightness value which varies depending upon an amount of current supplied thereto, a first TFT controlled by a scanning line for writing brightness information given thereto from a data line into the pixel, and a second TFT for controlling the amount of current to be supplied to the OLED corresponding to the brightness information written. Writing of the brightness information into each pixel is performed by applying an electric signal corresponding to the brightness information to the data line while the scanning line is selected.
    Type: Grant
    Filed: June 15, 2000
    Date of Patent: June 24, 2003
    Assignee: Sony Corporation
    Inventors: Mitsunobu Sekiya, Akira Yumoto
  • Publication number: 20030107560
    Abstract: When a current-writing type pixel circuit is made, it involves a greater number of transistors and TFTs occupy much of the area of the pixel circuit. To alleviate this problem, two pixel circuits (P1, P2) have a first scanning TFT (14), a current-voltage conversion TFT (16), respective second scanning TFTs (15-1, 15-2), capacitors (131,13-2), and drive TFTs (12-1, 12-2) for OLED including organic EL elements (11-2, 11-2) of two pixels, for example, in a row direction. In each of the pixel circuits, the first scanning TFT (14) handling a large amount of current (Iw) as compare with current flowing through the OLED (11-2, 11-2), and the current-voltage conversion TFT (16) are shared between two pixels.
    Type: Application
    Filed: September 11, 2002
    Publication date: June 12, 2003
    Inventors: Akira Yumoto, Mitsuru Asano
  • Patent number: 6542142
    Abstract: A voltage generating circuit which enables realization of iminiaturization, reduction in operating voltage and reduction in dissipation power, a spatial light modulating element and a display system using the same, and a driving method for display system are disclosed. A pMOS transistor as first level setting means is controlled by a pre-charge signal and an output node is pre-charged to a first level. An nMOS transistor forming a control circuit is controlled in accordance with signals on a scanning line and a data line. A signal for controlling an nMOS transistor as second level setting means is generated to control the ON/OFF state of this transistor. Thus, electric charges are discharged from a capacitor and the output node is set at a second level. The capacitor holds the level of the output node and supplies the level to an electrode as a load.
    Type: Grant
    Filed: December 23, 1998
    Date of Patent: April 1, 2003
    Assignee: Sony Corporation
    Inventors: Akira Yumoto, Osamu Akimoto
  • Patent number: 6501466
    Abstract: Each of picture elements comprises an input transistor for accepting a signal current from a data line when a scanning line is selected, a conversion transistor for converting the signal current into a voltage and for holding thus converted voltage, and a drive transistor for driving a light emitting device with drive current corresponding to the converted voltage. The conversion transistor flows the signal current to its channel to generate the voltage corresponding to the converted voltage and a capacitor to restrain the generated voltage. Further the drive transistor flows the drive current corresponding to the voltage stored in the capacitor. In this case the threshold voltage of the drive transistor is set not to be smaller than the threshold voltage of the conversion transistor, and thereby a leakage current flowing through the light emitting device is suppressed.
    Type: Grant
    Filed: November 13, 2000
    Date of Patent: December 31, 2002
    Assignee: Sony Corporation
    Inventors: Machio Yamagishi, Akira Yumoto
  • Publication number: 20020196211
    Abstract: An active matrix type display apparatus of the present invention includes pixel circuits each having an electrooptic device that changes brightness thereof according to a current flowing therein and driving said electrooptic device on the basis of brightness data supplied via a data line, and a current type pixel driving circuit for supplying each of said pixel circuits with a writing current that temporally increases in magnitude of a current value thereof within a cycle of writing of said brightness data. In the matrix type display apparatus of the present invention, the magnitude of the current value of the writing current is temporally increased within the writing cycle, whereby the writing current is limited to a low level (or zero) in an early stage of the writing cycle. Thus, the average value of the writing current is reduced.
    Type: Application
    Filed: May 23, 2002
    Publication date: December 26, 2002
    Inventor: Akira Yumoto
  • Publication number: 20020195964
    Abstract: In an active matrix type organic EL display apparatus, a current bias circuit for feeding a data line with a current in a direction of canceling a writing current is provided for each data line. The current bias circuit includes: a converting unit supplied with information of a value of the driving current to be fed in a form of a current, for converting the supplied current into a form of a voltage; a retaining unit for retaining the voltage obtained by the conversion by the converting unit; and a driving unit for converting the voltage retained by the retaining unit into a current, and feeding the data line with the current as the driving current. The current bias circuit feeds, as a bias current, the driving current in the direction of canceling the brightness data current through each data line, and the value of the bias current is prevented from varying among the data lines.
    Type: Application
    Filed: May 29, 2002
    Publication date: December 26, 2002
    Inventor: Akira Yumoto
  • Publication number: 20020067328
    Abstract: A voltage generating circuit which enables realization of iminiaturization, reduction in operating voltage and reduction in dissipation power, a spatial light modulating element and a display system using the same, and a driving method for display system are disclosed. A pMOS transistor as first level setting means is controlled by a pre-charge signal and an output node is pre-charged to a first level. An nMOS transistor forming a control circuit is controlled in accordance with signals on a scanning line and a data line. A signal for controlling an nMOS transistor as second level setting means is generated to control the ON/OFF state of this transistor. Thus, electric charges are discharged from a capacitor and the output node is set at a second level. The capacitor holds the level of the output node and supplies the level to an electrode as a load.
    Type: Application
    Filed: December 23, 1998
    Publication date: June 6, 2002
    Inventors: AKIRA YUMOTO, OSAMU AKIMOTO
  • Patent number: 5132574
    Abstract: An output circuit for a memory device has four MOS transistors. A first MOS transistor and a second MOS transistor comprise an output stage of the output circuit, and a control circuit controls the voltages of the gates of the first and the second MOS transistors. A third MOS transistor has its source connected to the gate of the second MOS transistor, and a fourth MOS transistor has its source connected to the gate of the first MOS transistor. When the data which are supplied to the control circuit are changed, the third or the fourth MOS transistor assists the level shift of the gate of the second and the first MOS transistor at the beginning of the level shift. By continuing the level shift, the third or the fourth MOS transistor is turned off. As a result, the source-gate voltage of the third or the fourth MOS transistor becomes lower than its threshold voltage, so that the switching noise or ground noise is reduced.
    Type: Grant
    Filed: January 23, 1991
    Date of Patent: July 21, 1992
    Assignee: Sony Corporation
    Inventor: Akira Yumoto